You said general marketing abilities, Right. So can I take a step back? I'd say that most of those suggestions are more about almost technical skills. Good ones (the ones I'm familiar with anyway)
You might go with University textbooks. Usually marketing degrees/ majors will comprise of courses along the lines of:
1)
intro to marketing courses (mostly about terminology and some simple case studies not very interesting as a rule but good place to make sure that you understand the terms and concepts assumed everywhere else)
2)
marketing management courses (kind of a linear progression form intro to marketing, sort of advanced intro to marketing)
3)
Consumer Behaviour courses (often very technical research based areas, not a fun read.Sace studies are almost like research papers)
4)
Market Research courses (Basically an area of statistics with specific expirement design/sampling methods relevent tomarketing) *very applicable online
5)
sepcialised area courses (international marketing, commodity goods marketing, e-marketing, retail,e-tail, etc)
6)
Marketing Strategy (almost always at least one mandatory course. Very Case study centred, very interesting)
If you really are serious about getting educated in marketing, you'll probably want to touch on all these a little and delve into some of them a lot. That's basically what you'd do in a marketing degree.
If you want to DIY go to a university secondhand bookshop (or website) and get the previous edition books (they are just as good for DIY). They'll usually be called something like the name of the course so they're easy to spot. Should only set you back $10-$20 a piece ($50-$150 new current editions).
If you want to research a bit, See what is the textbook for the marketing subject you want to study.
You can look at my old Uni's if you want
http://ecocomm.anu.e...discipline=MKTG. If you like the course descritpition, get the textbook.
If you are actually looking for suggustions, I would suggest starting from the end- Marketing Strategy.
-First of all, its the most interesting because its usually case study heavy.
-Secondly I'd prefer to pick up lingo/terms allong the way rather then actually have them properly explained.
-Most importantly, when you subsequently go into other areas of marketing it will be with application in mind. So when you go back to something like consumer behaviour, or market research, you have already heard/learned about the power and impact that getting this right can have on results.